As 2018 heads to it's inevitable conclusion I've had an opportunity to look back over the last 12 months and the jobs Pro Harmonic has entertained. Straight ahead repair work never lets up. This year I repaired over 200 items of equipment. The repairs ranged from...

A while back I had the pleasure of refurbishing a Vox 730. This very rare amplifier was almost the sole amp used on the Beatles' Sgt. Peppers and Revolver albums. Here's a look inside. https://youtu.be/6KAcG5HY2-s

A very early Avalon 737 came in for a routine service this week. Its owner, a local chap is an old school buddy of Wyn Morro, the man behind Avalon Design He reminded me that it was this very Avalon 737 that was the first to have a fast attack modification performed...

Here at Pro Harmonic our Broadcast products are built by hand in an Australian Shed. We have been busy refining the Head Band Pure Performance Headphone amplifier following the prototype's successful Groovin' the Moo tour. Here's a video of the new version being...

As is the way with all Broadcast products, they arise from repeated requests for a custom device with similar requirements. I've built hundreds of headphone amps and was receiving a number of requests for stage headphone amps. A loud, high performance amp is a given,...

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We work in a complex world that combines technology with technique, machinery with magic, all of it creating lots of potential for things to go wrong. And it’s when things go wrong that we often make our biggest mistake – we make assumptions. Whether troubleshooting a...

I felt a shudder down the phone line when I mentioned the words ‘5000 series’ to the man at the other end of the line, and my own shudder upon hearing his carefully worded response: ‘we don’t have any documentation and we don’t have any spare parts

Here on the workbench there’s one electronic component above all others that I deal with on a daily basis. Whether I’m refurbishing an old ’50s tube limiter, repairing console channel strips or hunting down an intermittent crackle in a microphone, capacitors are...

The pad is one of the most obvious of audio control functions: flick the switch and the signal level drops by the prescribed amount; flick it again and the signal is restored. Here we’ll explore why we need them, how to design them and importantly how you can build...

As a teenager I’d spend hours sitting in front of the family’s old gramophone (yes it had tubes) playing Led Zeppelin records. My dad would walk in yelling: “what the hell is that noise?” I wish I’d known enough back then to say – as I lifted the needle of the record...

Faffing around with cables, adapters and cranking volume controls back and forth between selections of different sources can easily be avoided by correctly interfacing with any iThing that may come through the door

If your studio monitoring is currently managed by something you inherited from your brother’s ’80s Dick Smith hi-fi, isn’t it high time you faced the music and found a more accurate means of listening to your system?

Efficient and effective troubleshooting is as much an attitude as it is a skill. It requires a logical and ordered approach that is best supported by the foundations laid down in the organisation and order of your studio or equipment setup.

Ultimately, amplifier performance hinges on the overall design, whether Class-A, Class-AB, valve, transistor or FET, the synergy of the combination of the individual parts and how feedback is employed determines an amplifier’s sonic stamp.